This invention relates generally to the premature detonation of missile warheads, and more specifically to the detonation of radar operated proximity fuzes in surface to air missiles.
By retransmitting a missile radar signal it is possible to provide a missile fuze with an erroneous target indication. Although proximity and variable time fuzes have been utilized on antiaircraft artillery shells and surface to air missiles for some time, improvements have been recently made to avoid the problems of premature detonation caused by clouds, rain, objects, dropped from aircraft, and even flights of birds. As a result of these improvements, electronic countermeasures designed to degrade the performance of surface-to-air missiles has become increasingly more difficult.
Surface to air missiles presently being utilized measure the power level of the return signal and require that a predetermined threshold be exceeded before the fuze will be activated to detonate the warhead. In addition, to avoid counter measures which merely send out the appropriate signal and detonate the warhead, the recent systems require that the frequency of the received signal simultaneously undergo a rapid change indicative of missile flyby.
Therefore only the combination of an increase in power level and a simultaneous frequency change will cause the activation of the fuze and missile detonation. Hence, in order to cause a premature detonation these requirements must be met.